Evan Ebel served several years in solitary confinement and had been recently paroled. / Colorado Department of Corrections via AP

by William M. Welch and Doug Stanglin, USA TODAY

by William M. Welch and Doug Stanglin, USA TODAY

Ballistics tests confirm that the gun that killed Colorado prisons chief Tom Clements was used last week by a parolee who died after a shootout with Texas police, authorities said Monday afternoon.

The El Paso County Sheriff's Office in Colorado Springs said that "unique and often microscopic markings" found on shell casings in Texas and Colorado led investigators to determine that the gun belonged to Evan Ebel, 28.

Officials did not release the caliber or make of Ebel's gun.

"To safeguard the investigation, we will not provide details on what our investigators have learned thus far, nor will we share details in the future until such time the information does not jeopardize the investigation," the sheriff's office said in a statement..

Still unknown is whether Ebel acted alone in killing Clements, 58, when Clements answered the front door of his home in Monument, north of Colorado Springs, on Tuesday night.

"Some of the unanswered questions right now are, did Mr. Ebel act alone, and if he did, what was his role in this particular crime?'' said Lt. Jeff Kramer, El Paso County sheriff's spokesman. "What was the motive of this crime? We don't have the answers to that yet.''

He confirmed that Ebel was a member of 211 Crew, a white supremacist prison gang. One theory investigators are pursuing is that a gang leader inside the Colorado prison where Ebel served time may have been collaborating with him or directing his actions, Kramer said.

Kramer said he did not know if the gun had been linked to the March 17 slaying of Denver pizza delivery driver Nathan Leon or to other shootings.

Ebel died Thursday after a wild chase through two northern Texas counties ended in a gunfight that mortally wounded him. He was shot in the head, then later taken off life support at a Forth Worth hospital.

Ebel was paroled in January. In 2005, he was sentenced to eight years in prison for a carjacking in which he pistol whipped the driver and later crashed the car in Commerce City, Colo.

Last month, Colorado prison officials broke up a core group of white supremacist leaders at Sterling Correctional Complex, transferring some to another facility, prison officials toldThe Denver Post.

The 211 Crew -- the name refers to the California penal code designation for robbery -- was founded in 1995 in the Denver County Jail by Benjamin Davis, who is serving a 108-year sentence for racketeering, conspiracy and solicitation to commit assault. He has been identified as a "shot caller" -- an inmate who can order hits.

The gang, which numbers between 200 and 1,000 members, carries out deadly retributions in prison and earns money running methamphetamine and guns outside prison, said Mark Potok, a senior fellow at the Southern Poverty Law Center. The money is funneled back to gang leaders serving time, he said.

Monday's ballistics announcement came hours after friends, co-workers and Colorado Gov. John Hickenlooper turned out at a memorial service for Clements.

His grief-stricken widow said her husband would want justice for his killer but also "forgiveness."

"Last Tuesday night, Tom and I were watching TV and the doorbell rang. And my life was forever changed," Lisa Clements, flanked by their two daughters, told the crowd at New Life Church in Colorado Springs.

She said her husband believed in the cause of corrections and felt that anyone can be redeemed -- even his own killer.

"Tom believed in redemption, in the ability of the human heart to be changed," she said. "We pray for forgiveness and peace for the family of the man suspected of taking Tom's life, and we pray every day for forgiveness and peace in our own hearts."

Hickenlooper, who hired Clements, praised him as "one of the finest people I've ever worked with."

A visibly shaken Hickenlooper, who told mourners he would "try to keep it together," said Clements had been dedicated to his work, particularly in trying to increase mental health services for inmates and to fight recidivism.

"He recognized that 97% of inmates in prison are going to be coming back and living as neighbors and we better focus on what we are going to do about it," Hickenlooper said.

Hickenlooper has said that he is a longtime friend of the suspect's father, attorney Jack Ebel, who testified two years ago before state lawmakers that solitary confinement was destroying his son's psyche.

The governor has confirmed that he mentioned the case to Clements as an example of why the prison system needed fixes before the job was offered, but the governor said he did not mention Evan Ebel by name.

There was no indication that Hickenlooper's relationship with the Ebels played a role in the shooting. Hickenlooper said he did not have any role in Evan Ebel's recent parole.